Chun Chang created DRILL-1690:
---------------------------------
Summary: Issue with using HBase plugin to access row_key only
Key: DRILL-1690
URL: https://issues.apache.org/jira/browse/DRILL-1690
Project: Apache Drill
Issue Type: Bug
Reporter: Chun Chang
#Thu Nov 06 11:38:17 PST 2014
git.commit.id.abbrev=eeb7160
Configure an HBase plugin to access MapRDB table. When, select the row key
only, we return two columns:
0: jdbc:drill:schema=M7> select row_key, fivecf from m7student limit 2;
+------------+------------+
| row_key | fivecf |
+------------+------------+
| [B@31966bd8 | {"create_date":"MjAxNC0wNS0yNyAwMDoyNjowNw=="} |
| [B@a824b57 | {"create_date":"MjAxNC0wMy0yNCAyMTo1NzozMw=="} |
+------------+------------+
2 rows selected (0.128 seconds)
0: jdbc:drill:schema=M7> select row_key from m7student limit 2;
+------------+------------+
| row_key | fivecf |
+------------+------------+
| [B@2560bab1 | {"create_date":"MjAxNC0wNS0yNyAwMDoyNjowNw=="} |
| [B@7180cda2 | {"create_date":"MjAxNC0wMy0yNCAyMTo1NzozMw=="} |
+------------+------------+
2 rows selected (0.107 seconds)
Here is the plan:
0: jdbc:drill:schema=M7> explain plan for select row_key from m7student limit 2;
+------------+------------+
| text | json |
+------------+------------+
| 00-00 Screen
00-01 SelectionVectorRemover
00-02 Limit(fetch=[2])
00-03 Scan(groupscan=[HBaseGroupScan [HBaseScanSpec=HBaseScanSpec
[tableName=m7student, startRow=null, stopRow=null, filter=null],
columns=[SchemaPath [`row_key`]]]])
| {
"head" : {
"version" : 1,
"generator" : {
"type" : "ExplainHandler",
"info" : ""
},
"type" : "APACHE_DRILL_PHYSICAL",
"options" : [ ],
"queue" : 0,
"resultMode" : "EXEC"
},
"graph" : [ {
"pop" : "hbase-scan",
"@id" : 3,
"hbaseScanSpec" : {
"tableName" : "m7student",
"startRow" : "",
"stopRow" : "",
"serializedFilter" : null
},
"storage" : {
"type" : "hbase",
"config" : {
"hbase.table.namespace.mappings" : "*:/test/tables"
},
"size.calculator.enabled" : false,
"enabled" : true
},
"columns" : [ "`row_key`" ],
"cost" : 1048576.0
}, {
"pop" : "limit",
"@id" : 2,
"child" : 3,
"first" : 0,
"last" : 2,
"initialAllocation" : 1000000,
"maxAllocation" : 10000000000,
"cost" : 1048576.0
}, {
"pop" : "selection-vector-remover",
"@id" : 1,
"child" : 2,
"initialAllocation" : 1000000,
"maxAllocation" : 10000000000,
"cost" : 1048576.0
}, {
"pop" : "screen",
"@id" : 0,
"child" : 1,
"initialAllocation" : 1000000,
"maxAllocation" : 10000000000,
"cost" : 1048576.0
} ]
} |
+------------+------------+
Drill should strip out the second column.
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